1. Field of the Invention
The invention relates to a coaxial insertion-type connector having a coupling nut and to an insertion-type connection comprising a coaxial insertion-type connector and a mating insertion-type connector.
2. Description of Related Art
In the form of what are referred to as BNC connectors, (coaxial) insertion-type connectors of the generic kind are described in IEC 61169-8, MIL-PRF39012, and CECC 22120. They are used in particular for transmitting radio-frequency signals. BNC connectors comprise a center conductor and an outer conductor surrounding the center conductor. The center and outer conductors are separated from one another by means of an insulating body (a dielectric). The electrical connection between two complementary insertion-type connectors is made by means of radial contacts between the center conductors and between the outer conductors. For this purpose, a center conductor and an outer conductor each take the form of slotted shells in which a center conductor and an outer conductor, in pin form, of the other insertion-type connector respectively engage. The elastic expansion and tightening of the slotted shells which go hand in hand with this produce a radial contact-making pressure. The mechanical connection is made by means of a bayonet joint in which, in a press-and-turn movement, two projections on one insertion-type connector are inserted into two L-shaped locking slots in a coupling nut on the other connector and then latch into undercuts at the ends of the locking slots. The axial force required to make the latched connection is usually applied by means of spring members which are compressed as the projections are inserted into the locking slots. To make it possible for manual plugging-together of the insertion-type connection to be easy, it is necessary for the spring constant of the spring members to be designed to be relatively low. However, this low spring constant may cause the problem that the two connectors move relative to one another when even only a low tractive force is exerted on the insertion-type connection, which may result in irregularities in signal transmission.
What is more, due to its principle, the latched position of the bayonet joint is fixed, and this too may have an adverse effect on the transmitting performance of the insertion-type connection. Because of tolerances on the dimensions of the insertion-type connectors, the axial air-gaps between the center conductors and between the outer conductors are relatively undefined, which may have an adverse effect on the repeatability of the transmitting performance.
To avoid the disadvantages of classic BNC insertion-type connections, what are referred to as precision BNC connections have been developed (see for example DE 103 06 053 B4 and DE 10 2004 017 803 B4). Instead of a slotted outer-conductor contact-making shell, these have a solid, tubular, outer-conductor contact-making shell with which contact is made at the end-face. The outer-conductor plug of the mating insertion-type connector has a shoulder extending round in a loop on its inside. Provision is also made for the replacement of the solid dielectric used in classic BNC insertion-type connectors by a precision support. These two provisions are able to produce a considerably improved transmitting performance. To enable a sufficiently high axial contact-making pressure to be achieved and to enable this to be maintained even when a tensile force is applied to the insertion-type connection, provision is made for the insertion-type connectors to be pressed against one another axially by the tightening of a ring nut connected to the coupling nut.
Precision BNC connectors have the disadvantage that they are not compatible with classic BNC connectors.